HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by GRUNE, T. Articles by DAVIES, K. J. A. Search for Related Content PubMed PubMed Citation Articles by GRUNE, T. Articles by DAVIES, K. J. A.

Ezrin turnover and cell shape changes catalyzed by proteasome in oxidatively stressed cells

TILMAN GRUNE^*,¶, THOMAS REINHECKEL, JAMES A. NORTH^*, RUI LI^*, PALOMA B. BESCOS^*,1, RESHMA SHRINGARPURE^* and KELVIN J. A. DAVIES^*2

^* Ethel Percy Andrus Gerontology Center and Division of Molecular & Computational Biology, the University of Southern California, Los Angeles, California, USA;
^¶ Clinics of Physical Medicine and Rehabilitation, Medical Faculty (Charité), Humboldt-University Berlin, Berlin, Germany; and
Centre of Surgery and Institute of Clinical Chemistry, Otto von Guericke University Magdeburg, Magdeburg, Germany

²Senior and corresponding author: Ethel Percy Andrus Gerontology Center, 3715 McClintock Ave., Room 306, University of Southern California, Los Angeles, CA 90089-0191, USA. E-mail: kelvin{at}usc.edu

We find that ezrin, a cytoskeletal protein involved in anchoring actin to the cell membrane, is preferentially degraded and resynthesized after oxidative stress. Ezrin was identified using 2-dimensional gels and amino-terminal microsequencing as one of a select few [³⁵S]methionine prelabeled proteins degraded in clone 9 rat liver cells exposed to hydrogen peroxide (H₂O₂). Metabolic labeling of cellular proteins with [³⁵S]methionine after oxidative stress showed that resynthesis of ezrin rose dramatically but carboxyl terminus anti-ezrin monoclonal antibodies revealed constant intracellular ezrin levels; in other words, degradation and resynthesis were exactly matched. Ezrin degradation was blocked by selective inhibitors of the proteasome (lactacystin, NLVS, and epoxomycin) and by an antisense oligonucleotide directed against the proteasome C2 subunit. H₂O₂ also caused major changes in cell shape, including significant increases in cell diameter, which must require substantial cytoskeletal rearrangement. Peroxide-induced increases in cell diameter were, however, blocked by the selective proteasome inhibitor lactacystin. The degradation and resynthesis of ezrin may therefore be an underlying mechanism for overall cell shape changes observed during oxidative stress. Oxidative stress induces extensive protein oxidation and degradation and significant increases in cell blebbing, rounding-up, and overall size. Our results indicate that all these oxidant-induced changes may actually be catalyzed by the proteasome.—Grune, T., Reinheckel, T., North, J. A., Li, R., Bescos, P. B., Shringarpure, R., Davies, K. J. A. Ezrin turnover and cell shape changes catalyzed by proteasome in oxidatively stressed cells.

Key Words: radixin • hydrogen peroxide • ezrin degradation • lactacystin • free radicals • proteolysis

This article has been cited by other articles:

				F. A. Wald, A. S. Oriolo, A. Mashukova, N. L. Fregien, A. H. Langshaw, and P. J. I. Salas Atypical protein kinase C (iota) activates ezrin in the apical domain of intestinal epithelial cells J. Cell Sci., March 1, 2008; 121(5): 644 - 654. [Abstract] [Full Text] [PDF]

				M. Endemann, H. Bergmeister, B. Bidmon, M. Boehm, D. Csaicsich, L. Malaga-Dieguez, K. Arbeiter, H. Regele, K. Herkner, and C. Aufricht Evidence for HSP-mediated cytoskeletal stabilization in mesothelial cells during acute experimental peritoneal dialysis Am J Physiol Renal Physiol, January 1, 2007; 292(1): F47 - F56. [Abstract] [Full Text] [PDF]